Photo-radiation source

ABSTRACT

A method of manufacturing a photo-radiation source comprising the steps of providing a first planar conductor; disposing a formation of light emitting chips on the first planar conductor, each chip having a cathode and an anode, one of the cathode and anode of each chip being in contact with the first planar conductor. The method of manufacturing a photo-radiation source also includes the steps of disposing a second planar conductor on top of a formation of light emitting chips so that the second planar conductor is in contact with the other of the cathode and anode of each chip; and binding the first planar conductor to the second planar conductor to permanently maintain the formation of light emitting chips without the use of solder or wiring bonding for making an electrical and mechanical contact between the chips and either of the first planar conductor and the second planar conductor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional application of and claims thebenefit under 35 U.S.C. §120 of U.S. patent application Ser. No.10/919,915 filed Aug. 17, 2004 which is a U.S. Utility Application ofU.S. Provisional Application Ser. No. 60/556,959, filed Mar. 29, 2004.This application also relates to U.S. Utility application Ser. No.10/920,010 entitled Light Active Sheet Material and U.S. Utilityapplication Ser. No. 10/919,830 entitled Light Active Sheets And MethodsFor Making The Same, both filed Aug. 17, 2004. The subject matter of theabove mentioned patent documents is incorporated by reference herein inits entirety.

BACKGROUND OF THE INVENTION

The present invention pertains to an inorganic light emitting diodelight sheet and methods for manufacturing the same. More particularly,the present invention pertains to an inorganic light emitting diodelight sheet that can be used as a photo-radiation source forapplications including, but not limited to, general illumination,architectural lighting, novelty lighting, display backlighting, heads-updisplays, commercial and roadway signage, monochromatic and full-colorstatic and video displays, radiation-source for photo-curable materials,patterned light emissive images, and the like. Further, the presentinvention pertains more particularly to an inorganic light active sheetthat can be used as a light-to-energy device for convertingphoto-radiation to electrical energy for applications including, but notlimited to, solar panels, CCD-type cameras, photo-sensors, and the like.Further, the present invention pertains more particularly, to methodsfor mass-producing the inventive light active sheet at relatively lowcost.

Inorganic light emitting diodes (LED) are based on elements of theperiodic table of a vast variety. They come out of semiconductortechnology, and indeed, a semiconductor diode such as a silicon diode,or a germanium diode were among the first semiconductor devices. Thesewere made by doping the silicon or the germanium with a small amount ofimpurity to make n-type (excess electrons) or p-type (excess holes) inthe material. LEDs emit light because of the materials selected so thatthe light is emitted in the ultra-violet, visible, or infrared ranges ofthe spectrum. The types of materials used are made from vapor depositionof materials on semiconductor wafers and cut into dice (a single one isa die). Typically, the die, or LED chips, are about 12 mil sq. Thecomposition of the chips depends on the color, for example some redchips are AlInGaAs and some blue chips are InGaN. The variations aretypically “three-five” variations, so-called because they vary based onthe third and fifth period of the periodic table to provide the n- andp-type materials.

The conversion of an LED chip into an LED lamp is a costly process,involving very precise handling and placement of the tiny LED chip. TheLED chips are most simply prepared as 3 mm LED lamps. The chip isrobotically placed in a split cup with electrodes on each side. Theentire structure is encased in a plastic lens that attempts to focus thebeam more narrowly. High brightness chips may also be surface mountedwith current-driving and voltage limiting circuits, and elaborate heatsink and heat removal schemes. Connection is by soldering or solderlessultrasonic wire bond methods. The result is a discrete point source oflight. The LED lamp has a pair of leads, which can then be soldered to aprinted circuit board. The cost of forming the lamp and then solderingthe lamp to a printed circuit board is a relatively expensive process.Accordingly, there is a need to reduce the cost of forming a lightemitting device based on the LED chip.

As an example application of LED lamps, it has recently been shown thatultraviolet LED lamps can be used to cure photo-polymerizable organicmaterials (see, for example, Loctite® 7700 Hand Held LED Light Source,Henkel-Loctite Corporation, Rocky Hill, Conn.

Photo-polymerizable organic materials are well known and are used forapplications such as adhesives, binders and product manufacturing.Photo-polymerization occurs in monomer and polymer materials by thecross-linking of polymeric material. Typically, these materials arepolymerized using radiation emitted from sources of light includingintensity flood systems, high intensity wands, chambers, conveyors andunshielded light sources.

As an example use of photo-polymerizable organic materials, precisionoptical bonding and mounting of glass, plastics and fiber optics can beobtained with photo-polymerizable adhesives. These materials can be usedfor opto-mechanical assembly, fiber optic bonding and splicing, lensbonding and the attachment of ceramic, glass, quartz, metal and plasticcomponents.

Among the drawbacks of the conventional systems that utilizephoto-polymerizable organic materials is the requirement of a highintensity photo-radiation source. Typically, light sources, such asmercury vapor lamps, have been used to generate the radiation needed forphoto-polymerization. However, these light sources are an inefficientradiation source because most of the energy put in to drive the lamp iswasted as heat. This heat must be removed from the system, increasingthe overall bulk and cost. Also, the lamps have relatively short servicelife-times, typically around 1000 hours, and are very costly to replace.The light that is output from these light sources usually covers a muchbroader spectrum than the photo-radiation wavelengths that are neededfor photo-polymerization. Much of the light output is wasted. Also,although the material can be formulated to be hardened at otherwavelengths, the typical photo-polymerizable organic material ishardened at one of the peak output wavelengths of the mercury vaporlamp, to increase the polymerization efficiency. This peak outputwavelength is in the UV region of the radiation spectrum. This UVradiation is harmful to humans, and additional shielding and protectiveprecautions such as UV-filtering goggles are needed to protect theoperators of such equipment.

FIG. 66 is a side view of an inorganic LED chip available. Aconventional inorganic LED chip is available from many manufacturers,typically has a relatively narrow radiation emission spectrum, isrelatively energy efficient, has a long service life and is solid-stateand durable. The chip shown is an example of an AlGaAs/AlGaAs red chip,obtained from Tyntek Corporation, Taiwan. These chips have dimensionsroughly 12 mil.times.12 mil.times.8 mil, making them very small pointlight sources. As shown in FIG. 67, in a conventional LED lamp, thischip is held in a metal cup so that one electrode of the chip (e.g., theanode) is in contact with the base of the cup. The metal cup is part ofa cathode lead. The other electrode of the chip (e.g., the cathode) hasa very thin wire solder or wiring bonding to it, with the other end ofthe wire solder or wiring bonding to an anode lead. The cup, chip, wireand portions of the anode and cathode leads are encased in a plasticlens with the anode and cathode leads protruding from the lens base.These leads are typically solder or wire bonded to a circuit board toselectively provide power to the chip and cause it to emit light. It isvery difficult to manufacture these conventional lamps due to the verysmall size of the chip, and the need to solder or wire bond such a smallwire to such a small chip electrode. Further, the plastic lens materialis a poor heat conductor and the cup provides little heat sink capacity.As the chip heats up its efficiency is reduced, limiting the serviceconditions, power efficiency and light output potential of the lamp. Thebulkiness of the plastic lens material and the need to solder or wirebond the lamp leads to an electrical power source limits emissive sourcepacking density and the potential output intensity per surface area.

There is a need for a photo-radiation source that is energy efficient,generates less heat, is low cost and that has a narrow spectrum ofradiation emission. There have been attempts to use inorganic lightemitting diode lamps (LEDs) as photo-radiation sources. Usually, theseLEDs are so-called high brightness UV radiation sources. A typical LEDconsists of a sub-millimeter sized chip of light emitting material thatis electrically connected to an anode lead and a cathode lead. The chipis encased within a plastic lens material. However, the processing thattakes the LED chips and turns it into an LED lamp is tedious andsophisticated, mostly due to the very small size of the LED chip. It isvery difficult to solder or wire bond directly to the chips, and so itis common practice to use LED lamps that are then solder or wire bondedonto a circuit board. Conventionally, UV LED lamps have been solder orwire bonded onto a circuit board in a formation to create a source ofphoto-radiation for photo-polymerizable organic materials.

This solution is far from optimum, since the relatively high cost of theLED lamps keeps the overall cost of the photo-radiation source high.There is a need for a photo-radiation source that can use the LED chipsdirectly, without the need for the lamp construction or a direct solderor wire bonded connection between the anode and cathode of the chip.Such as system would have an efficient chip packing density, enabling ahigh-intensity photo-radiation source having a narrow emission band.

SUMMARY OF THE INVENTION

The present invention is intended to overcome the drawbacks of the priorart. It is an object of the present invention to provide methods formanufacturing solid-state light active devices. It is another object ofthe present invention to provide device structures for solid-state lightactive devices. It is still another object of the present invention toprovide a photo-radiation source for the selective polymerization ofphoto-radiation-curable organic material.

In accordance with an aspect of the invention, a method is provided forforming a sheet of light active material. A first substrate is providedhaving a transparent first conductive layer. A pattern of light activesemiconductor elements are formed. The light active semiconductorelements have an n-side and a p-side. Each light active semiconductorelement has either of the n-side or the p-side in electricalcommunication with the transparent conductive layer. A second substratehaving a second conductive layer is provided. The second substrate issecured to the first substrate so that the other of said n-side or saidp-side of each said light active semiconductor element in electricalcommunication with the second conductive layer. Thus, a solid-statesheet of light active material is formed.

The transparent first conductive layer may comprise a transparentcoating preformed on the first substrate. The transparent coating can beapplied as a conductive ink or conductive adhesive.

The pattern of light active semiconductor elements can be formed byelectrostatically attracting the light active semiconductor elements toa transfer member. Then, transferring the attracted light activesemiconductor elements from the transfer member to the first substrate.The transfer member may include an opto-electric coating effective forholding a patterned electrostatic charge. The patterned electrostaticcharge is effective for electrostatically attracting the light activesemiconductor elements and forming the pattern of light activesemiconductor elements. The optical patterning of the opto-electriccoating can be done, for example, using a scanned laser beam and an LEDlight source, similar to the process used by laser or LED printers.Thus, the transfer member may comprise a drum.

An adhesive pattern can be formed on the first substrate for adheringthe pattern of light active semiconductor elements to the firstsubstrate. Alternatively, or additionally, an adhesive pattern can alsobe formed on the first substrate for adhering the second substrate tothe first substrate.

A pattern of light active semiconductor elements can be formed byforming a first pattern of first light active semiconductor elements andforming a second pattern of second light active semiconductor elements.The first light active semiconductor elements emit light having a firstcolor and the second light active semiconductor elements emit lighthaving a second color. Alternatively, the first light activesemiconductor elements emit light and the second light activesemiconductor elements convert light to electrical energy.

The first conductive layer may be formed as a grid of x-electrodes, andthe second conductive layer formed as a grid of y-electrodes, so thateach respective light active semiconductor element is addressable forforming a sheet of light active material capable of functioning as apixilated display component.

The pattern of light active semiconductor elements can be formed byforming a first pattern of first color light emitting semiconductorelements, forming a second pattern of second color light emittingsemiconductor elements and forming a third pattern of third color lightemitting semiconductor element. The first conductive layer may be formedas a grid of x-electrodes, and the second conductive layer formed as agrid of y-electrodes, so that each respective light active semiconductoris addressable for forming a sheet of light active material capable offunctioning as a full-color pixilated display component.

In accordance with another aspect of the invention, a method is providedfor forming a light-emitting device. A first substrate is provided. Afirst conductive surface is formed on the first substrate. A pattern ofLED chips is formed on the conductive pattern. Each LED chip has ananode and a cathode side. A second substrate is provided. A secondconductive surface is formed on the second substrate. The firstsubstrate is fixed to the second substrate so that either of the anodeand the cathode side of the LED chip is in electrical communication withthe first conductive surface, and the other of the anode and the cathodeside of the LED chips is in electrical communication with the secondconductive surface.

The first conductive surface may be formed as a conductive patterncomprised of at least one of a conductive coating, a conductive ink anda conductive adhesive. At least one of the first and the secondconductive surface is a transparent conductor. At least one of the firstand the second conductive surface is preformed on the respective firstand second substrate. The first conductive surface can be formed using aprinting method. The printing method may comprise at least one of aninkjet printing method, a laser printing method, a silk-screen printingmethod, a gravure printing method and a donor transfer sheet printingmethod.

An adhesive layer may be formed between the top substrate and the bottomsubstrate. The adhesive layer may comprise at least one of a conductiveadhesive, a semi-conductive adhesive, an insulative adhesive, aconductive polymer, a semi-conductive polymer, and an insulativepolymer. A function-enhancing layer can be formed between the topsubstrate layer and the bottom substrate layer. The function-enhancinglayer includes at least one of a re-emitter, a light-scatterer, anadhesive, and a conductor.

The pattern of LED chips can be formed by electrostatically attractingthe LED chips to a transfer member, and then transferring the attractedLED chips from the transfer member to the first conductive surface. Thetransfer member may include an opto-electric coating effective forholding a patterned electrostatic charge, the patterned electrostaticcharge being effective for electrostatically attracting and forming thepattern of LED chips.

The opto-electric coating can be patterned using at least one of ascanned laser beam and an LED light source. The transfer member may be adrum, a flat planar member, or other shape.

In accordance with another aspect of the invention, a method is providedfor forming a light-to-energy device. A first substrate is provided. Afirst conductive surface is formed on the first substrate. A pattern ofsemiconductor elements is formed on the conductive pattern. Eachsemiconductor element comprises a charge donor side and a chargeacceptor side. A second substrate is provided. A second conductivesurface is formed on the second substrate. The first substrate is fixedto the second substrate so that either of the charge donor and thecharge acceptor side of the semiconductor elements is in electricalcommunication with the first conductive surface and the other of thecharge donor and the charge acceptor side of the semiconductor elementsis in electrical communication with the second conductive surface.

The first conductive surface is formed as a conductive pattern comprisedof at least one of a conductive coating, a conductive ink and aconductive adhesive. At least one of the first and the second conductivesurface is a transparent conductor. At least one of the first and thesecond conductive surface is preformed on the respective first andsecond substrate. The first conductive surface may be formed using aprinting method. The printing method may comprise at least one of aninkjet printing method, a laser printing method, a silk-screen printingmethod, a gravure printing method and a donor transfer sheet printingmethod.

An adhesive layer can be formed between the top substrate and the bottomsubstrate. The adhesive layer may comprise at least one of a conductiveadhesive, a semi-conductive adhesive, an insulative adhesive, aconductive polymer, a semi-conductive polymer, and an insulativepolymer. A function-enhancing layer can be formed between the topsubstrate layer and the bottom substrate layer, wherein thefunction-enhancing layer includes at least one of a re-emitter, alight-scatterer, an adhesive, and a conductor.

The pattern of LED chips can be formed by electrostatically attractingthe LED chips to a transfer member, and then transferring the attractedLED chips from the transfer member to the first conductive surface. Thetransfer member may include an opto-electric coating effective forholding a patterned electrostatic charge, the patterned electrostaticcharge being effective for electrostatically attracting and forming thepattern of LED chips. The opto-electric coating can be patterned usingat least one of a scanned laser beam and an LED light source. Thetransfer member may be shaped as a drum, a flat planar member, or othershape.

In accordance with another aspect of the invention, device structuresare provide for sheets of light active material. A first substrate has atransparent first conductive layer. A pattern of light activesemiconductor elements fixed to the first substrate. The light activesemiconductor elements have an n-side and a p-side. Each light activesemiconductor element has either of the n-side or the p-side inelectrical communication with the transparent conductive layer. A secondsubstrate has a second conductive layer. An adhesive secures the secondsubstrate to the first substrate so that the other of said n-side orsaid p-side of each said light active semiconductor element is inelectrical communication with the second conductive layer. Thus, asolid-state light active device is formed.

The transparent first conductive layer may comprise a transparentcoating preformed on the first substrate. The transparent coating can bea conductive ink or conductive adhesive. An adhesive pattern may beformed on the first substrate for adhering the pattern of light activesemiconductor elements to the first substrate. Alternatively, oradditionally, an adhesive pattern may be formed on the first substratefor adhering the second substrate to the first substrate.

The pattern of light active semiconductor elements may comprise a firstpattern of first light active semiconductor elements and a secondpattern of second light active semiconductor elements. The first lightactive semiconductor elements may emit light having a first color andthe second light active semiconductor elements emit light having asecond color. Alternatively, the first light active semiconductorelements may emit light and the second light active semiconductorelements convert light to electrical energy.

The first conductive layer may be formed as a grid of x-electrodes, andthe second conductive layer formed as a grid of y-electrodes. Eachrespective light active semiconductor element is disposed at therespective intersections of the x and y grid and are thus addressablefor forming a sheet of light active material capable of functioning as apixilated display component.

The pattern of light active semiconductor elements may comprise a firstpattern of first color light emitting semiconductor elements, a secondpattern of second color light emitting semiconductor elements and athird pattern of third color light emitting semiconductor element. Thefirst conductive layer may be formed as a grid of x-electrodes, and thesecond conductive layer being formed as a grid of y-electrodes. Therespective first, second and third color light emitting elements may bedisposed at the intersections of the x and y grid so that eachrespective light active semiconductor is addressable. Thus, a sheet oflight active material is formed capable of functioning as a full-colorpixilated display component.

In accordance with another aspect of the invention, a light-emittingdevice comprises a first substrate. A first conductive surface is formedon the first substrate. A pattern of LED chips is formed on theconductive pattern. Each LED chip has an anode and a cathode side. Asecond substrate has a second conductive surface formed on it. Anadhesive fixes the first substrate to the second substrate so thateither of the anode and the cathode side of the LED chip is inelectrical communication with the first conductive surface, and theother of the anode and the cathode side of the LED chips is inelectrical communication with the second conductive surface.

The first conductive surface can be formed as a conductive patterncomprised of at least one of a conductive coating, a conductive ink anda conductive adhesive. At least one of the first and the secondconductive surface is a transparent conductor. At least one of the firstand the second conductive surface can be preformed on the respectivefirst and second substrate. The first conductive surface can be formedusing a printing method. The printing method may comprise at least oneof an inkjet printing method, a laser printing method, a silk-screenprinting method, a gravure printing method and a donor transfer sheetprinting method.

The adhesive layer can comprise at least one of the top substrate andthe bottom substrate. The adhesive layer can comprise at least one of aconductive adhesive, a semi-conductive adhesive, an insulative adhesive,a conductive polymer, a semi-conductive polymer, and an insulativepolymer. A function-enhancing layer can be formed between the topsubstrate layer and the bottom substrate layer. The function-enhancinglayer may include at least one of a re-emitter, a light-scatterer, anadhesive, and a conductor.

In accordance with another aspect of the invention, a light-to-energydevice comprises a first substrate. A first conductive surface is formedon the first substrate. A pattern of semiconductor elements is formed onthe conductive pattern. Each semiconductor element includes a chargedonor layer side and a charge acceptor side. A second substrate isprovided having a second conductive surface formed on it. An adhesivefixes the first substrate to the second substrate so that either of thecharge donor and the charge acceptor side of the semiconductor elementsis in electrical communication with the first conductive surface, andthe other of the charge donor and the charge acceptor side of thesemiconductor elements is in electrical communication with the secondconductive surface.

The first conductive surface may be formed as a conductive patterncomprised of at least one of a conductive coating, a conductive ink anda conductive adhesive. At least one of the first and the secondconductive surface is a transparent conductor. At least one of the firstand the second conductive surface may be preformed on the respectivefirst and second substrate. The adhesive may comprise at least one ofthe top substrate and the bottom substrate. The adhesive layer maycomprise at least one of a conductive adhesive, a semi-conductiveadhesive, an insulative adhesive, a conductive polymer, asemi-conductive polymer, and an insulative polymer.

In accordance with another aspect of the present invention, thephoto-radiation source includes a first electrode with a secondelectrode disposed adjacent to the first electrode, and defining a gaptherebetween. A photo-radiation emission layer is disposed in the gap.The photo-radiation emission layer includes a charge-transport matrixmaterial and an emissive particulate dispersed within thecharge-transport matrix material. The emissive particulate receiveselectrical energy through the charge-transport matrix material appliedas a voltage to the first electrode and the second electrodephoto-radiation. The emissive particulate generates photo-radiation inresponse to the applied voltage. This photo-radiation is effective forthe selective polymerization of photo-radiation curable organicmaterial.

The charge-transport matrix material may be an ionic transport material,such as a fluid electrolyte or a solid electrolyte, including a solidpolymer electrolyte (SPE). The solid polymer electrolyte may be apolymer electrolyte including at least one of a polyethylene glycol, apolyethylene oxide, and a polyethylene sulfide. Alternatively oradditionally, the charge-transport matrix material may be anintrinsically conductive polymer. The intrinsically conductive polymermay include aromatic repeat units in a polymer backbone. Theintrinsically conductive polymer may be, for example, a polythiophene.

In accordance with another aspect of the present invention, aphoto-radiation source is provided for the selective polymerization ofphoto-radiation-curable organic material. A plurality of light emittingdiode chips generate a photo-radiation spectrum effective for theselective polymerization of photo-radiation-curable organic material.Each chip has an anode and a cathode. A first electrode is in contactwith each anode of the respective light emitting diode chips. A secondelectrode is in contact with each cathode of the respective lightemitting diode chips. At least one of the first electrode and the secondelectrode comprises a transparent conductor. The plurality of chips arepermanently fixed in a formation by being squeezed between the firstelectrode and the second electrode without the use of solder or wirebonding. The plurality of chips are permanently fixed in a formation bybeing adhered to at least one of the first electrode and the secondelectrode using a conductive adhesive, for example, the conductiveadhesive can be a metallic/polymeric paste, an intrinsically conjugatedpolymer, or other suitable material. The intrinsically conjugatedpolymer may comprise a benzene derivative. The intrinsically conjugatedpolymer may comprise a polythiophene. In accordance with this embodimentof the invention, ultra-high chip packing density is obtained withoutthe need for solder or wire bonding each individual chip.

In accordance with the present invention, a method of making aphoto-radiation source is provided. A first planar conductor is providedand a formation of light emitting chips formed on the first planarconductor. Each chip has a cathode and an anode. One of the cathode andanode of each chip is in contact with the first planar conductor. Asecond planar conductor is disposed on top of the formation of lightemitting chips, so that the second planar conductor is in contact withthe other of the cathode and anode of each chip. The first planarconductor is bound to the second planar conductor to permanentlymaintain the formation of light emitting chips. In accordance with thepresent invention, the formation is maintained, and the electricalcontact with the conductors is obtained, without the use of solder orwire bonding for making an electrical and mechanical contact between thechips and either of the first planar conductor and the second planarconductor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the inventive method for manufacturing a patternedlight active sheet;

FIG. 2 illustrates another inventive method for manufacturing a lightactive sheet;

FIG. 3 illustrates another inventive method for manufacturing a lightactive sheet having two or more different types of light activesemiconductor elements;

FIG. 4 is a cross-sectional view of an inventive light active sheethaving a conductive adhesive for fixing the substrates and/or the lightactive semiconductor elements in place;

FIG. 5 is a cross-sectional view of an inventive light active sheethaving two different types of light active semiconductor elementsoriented to be driven with opposite polarity electrical energy;

FIG. 6 is a cross-sectional view of an inventive light active sheethaving additives included between the substrates to improve the desiredlight active sheet properties;

FIG. 7 is a cross-sectional view of an inventive light active sheethaving the light active semiconductor elements disposed within asolid-state electrolyte;

FIG. 8 is a cross-section view of an inventive light active sheet havingthe light active semiconductor elements disposed within a solid-statecharge transport carrier;

FIG. 9 is a cross-section view of an inventive light active sheet havingan insulator material disposed between the top and bottom substrates;

FIG. 10 is a cross-sectional view of the inventive light active sheethaving an RGB semiconductor element pattern for forming a full-colorlight emissive display;

FIG. 11 is a cross-sectional view of the inventive light active sheethaving a transparent substrate with a convex lens system;

FIG. 12 is a cross-sectional view of the inventive light active sheethaving a transparent substrate with a concave lens system;

FIG. 13 is an exploded view of the inventive light active sheet having amelt adhesive mesh;

FIG. 14 is a schematic view of a method of manufacturing a light activesheet utilizing the melt adhesive mesh;

FIG. 15 is an exploded view of the inventive light active sheetcomprising a substrate having position-facilitating chip dimples;

FIG. 16 is a cross-sectional view of the inventive light active sheetshowing the position-facilitating chip dimples;

FIG. 17 is an exploded view of the light active sheet having adhesivedroplets for fixing the semiconductor elements (chips) to the substrateand/or for adhering the top substrate to the bottom substrate;

FIG. 18 is an exploded view of the light active sheet having anelectrical resistance-reducing conductive grid pattern;

FIG. 19 is a schematic view of an inventive method of manufacturing alight active sheet wherein a hole-and-sprocket system is employed toensure registration of the constituent parts of the inventive lightsheet during the manufacturing process;

FIG. 20 is an isolated view of an inventive semiconductor element (e.g.,LED chip) having a magnetically-attractive element to facilitate chiporientation and transfer;

FIG. 21 illustrates the use of a magnetic drum and electrostatic chargesource for orienting and transferring a pattern of semiconductorelements onto a substrate;

FIG. 22 illustrates the use of an electrostatic drum and magneticattraction source for orienting and transferring a pattern ofsemiconductor elements onto a substrate;

FIG. 23 illustrates an inventive light active sheet thermoformed into athree-dimensional article;

FIG. 24(a) illustrates an inventive light active sheet fabricated into alampshade form-factor having a voltage conditioner for conditioningavailable electrical current;

FIG. 24(b) illustrates an inventive light active sheet fabricated into alight-bulb form-factor having a voltage conditioner for conditioningavailable electrical current;

FIG. 25 is a cross-sectional view of an inventive light sheet employedin the light bulb form factor show in FIG. 24;

FIG. 26(a) illustrates an inventive light sheet configured as aheads-up-display (HUD) installed as an element of a vehicle windshield;

FIG. 26(b) is a block diagram showing a driving circuit for an inventiveHUD with a collision avoidance system;

FIG. 27 is an exploded view of an inventive light sheet utilized as athin, bright, flexible, energy efficient backlight component for an LCDdisplay system;

FIG. 28 schematically illustrates an embodiment of the inventivephoto-radiation source showing a semiconductor particulate randomlydispersed within a conductive carrier matrix;

FIG. 29 illustrates an embodiment of the inventive photo-radiationsource showing the semiconductor particulate aligned between electrodes;

FIG. 30 illustrates an embodiment of the inventive photo-radiationsource showing semiconductor particulate and other performance enhancingparticulate randomly dispersed within the conductive carrier matrixmaterial;

FIG. 31 illustrates an embodiment of the inventive photo-radiationsource showing different species of organic light active particulatedispersed within a carrier matrix material;

FIG. 32 schematically illustrates the cross-section of an embodiment ofthe inventive photo-radiation source;

FIG. 33 illustrates a step in an embodiment of the inventive method ofmaking a photo-radiation source, showing the step of the addition of anemissive particulate/matrix mixture onto a bottom substrate with bottomelectrode;

FIG. 34 illustrates a step in the inventive method of making aphoto-radiation source, showing the step of uniformly spreading theemissive particulate/matrix mixture onto the bottom electrode;

FIG. 35 illustrates a step in the inventive method of making aphoto-radiation source, showing the addition of a transparent topsubstrate with transparent top electrode over the emissiveparticulate/matrix mixture;

FIG. 36 illustrates a step in the inventive method of making aphoto-radiation source, showing the step of photo-curing the matrix toform a solid-state emissive particulate/hardened matrix on the bottomsubstrate;

FIG. 37 illustrates a step in the inventive method of making aphoto-radiation source, showing the step of trimming the solid-statephoto-radiation source sheet;

FIG. 38 illustrates the completed solid-state photo-radiation sourcesheet;

FIG. 39 illustrates the completed solid-state photo-radiation sourcesheet being driven with a driving voltage to light up;

FIG. 40 illustrates an embodiment of the inventive light sheet beingcut, stamped or otherwise shaped into a desired configuration;

FIG. 41 illustrates a cut configuration of the inventive light sheetmounted on a backing board;

FIG. 42 illustrates the cut configuration of the inventive light sheetlighting up when voltage is applied;

FIG. 43 illustrates the cut configuration of the inventive light sheetemployed for light emissive signage;

FIG. 44 shows an example of a roll-to-roll manufacturing processutilizing the inventive photo-radiation source for curing aphoto-polymerizable organic material disposed between two continuoussheets of top and bottom substrates;

FIG. 45 shows an example of a conveyor continuous processing systemutilizing a curing booth having the inventive photo-radiation source;

FIG. 46 shows an example of a light-pipe photo-polymerization systemhaving an embodiment of the inventive photo-radiation source;

FIG. 47 shows an example of a three-dimensional scanned curing systemhaving an embodiment of the inventive photo-radiation source;

FIG. 48 illustrates a conventional inorganic light emitting diode chip;

FIG. 49 illustrates an inventive photo-radiation (light active) sourceor sensor having a formation of light emitting diode chips connectedwithout solder or wire bonding to a common anode and cathode;

FIG. 50 illustrates the high packing density of the formation of lightemitting diode chips obtainable in accordance with an embodiment of theinventive photo-radiation source;

FIG. 51 is an embodiment of the inventive photo-radiation source showinga heat sink electrode base having cooling channels;

FIG. 52 illustrates an embodiment of the inventive photo-radiationsource having a geometry and optical system for concentrating the lightoutput for photo-curing an organic material in a continuous fabricationmethod;

FIG. 53 shows an isolated view of a substrate with an optical surfacefor controlling the focus of light emitted from an embodiment of theinventive photo-radiation source;

FIG. 54 shows an embodiment of the inventive photo-radiation sourcehaving a flat light sheet construction with a top substrate with anoptical surface;

FIG. 55 shows the inventive photo-radiation source having a curved lightsheet construction shaped with a light emission enhancing curvature;

FIG. 56 is a schematic side view of the curved light sheet constructionillustrating the focal point of light emission;

FIG. 57 is a view of the curved light sheet construction having asecondary optical system for controlling the focus of light emission;

FIG. 58 is a schematic side view showing light emitting diode chipsdisposed adjacent to respective optical lenses;

FIG. 59 is a schematic side view showing how the light output intensitycan be increased by changing the shape of the curved light sheetconstruction;

FIG. 60 is a schematic side view showing two curved light sheets havinga common light emission focal point;

FIG. 61 is a schematic side view showing three curved light sheetshaving a common light emission focal point;

FIG. 62 is cross-sectional block diagram showing the constituent partsof the inventive light active sheet;

FIG. 63 is a cross-section block diagram of an embodiment of theinventive light active sheet having a cross-linked polymer (e.g.,polysiloxane-g-oglio9ethylene oxide) matrix, UV semiconductor elements,and phosphor re-emitter;

FIG. 64 is a cross-sectional block diagram of an embodiment of theinventive light active sheet having a light diffusive and/or re-emittercoating on a transparent substrate;

FIG. 65 is a cross-sectional block diagram of an embodiment of theinventive light active sheet having blue and yellow semiconductorelements, and light diffusers (e.g., glass beads) within the matrix;

FIG. 66 is a side view of a commercially available inorganic LED chip;FIG. 67 is a cross-sectional view of a conventional LED lamp;

FIG. 68 is a cross-sectional view of an experimental prototype of theinventive photo-radiation source having a gap between the N electrode ofan LED chip and an ITO cathode;

FIG. 69 is a cross-sectional view of the experimental prototype of theinventive photo-radiation source having a drop of quinoline as aconductive matrix material completing the electrical contact between theN electrode of the LED chip and the ITO cathode;

FIG. 70 is a photograph of an experiment prototype demonstrating a lightactive particle (LED chip) connected to a top and/or bottom electrodethrough a charge transport material (quinoline);

FIG. 71 is a photograph of an experimental prototype demonstrating afree-floating light emissive particulate (miniature LED lamps) dispersedwithin a conductive fluid carrier (salt-doped polyethylene oxide); and

FIG. 72 is a photograph of an experiment prototype demonstrating an8.times.4 element grid of light active semiconductor elements (LEDchips) disposed between ITO-coated glass substrates.

DETAILED DESCRIPTION OF THE DRAWINGS

For purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, there being contemplated such alterationsand modifications of the illustrated device, and such furtherapplications of the principles of the invention as disclosed herein, aswould normally occur to one skilled in the art to which the inventionpertains.

FIG. 1 illustrates the inventive method for manufacturing a patternedlight active sheet. In accordance with the present invention, asolid-state light active sheet is provided, and a method formanufacturing the same. The solid-state light active sheet is effectivefor applications such as flexible solar panels and light sensors, aswell as high efficiency lighting and display products. The inventivelight sheet utilizes semiconductor elements, such as commerciallyavailable LED chips, to create a totally new form of solar panel,lighting, signage and display devices. The light sheet can beconstructed to provide an even, diffuse solid-state lighting device thatis ultra-thin, flexible and highly robust. An embodiment of theinventive manufacturing method is based on the well-known physics andmechanical and electrical components found in a conventional desktoplaser printer. In essence, in accordance with this inventive embodiment,LED chips replace the toner of a laser printer. The result is a uniquelight sheet form factor adaptable to an extraordinarily broad range ofapplications. These applications range from interior tent lighting, todisplay backlighting, to commercial and municipal signage and trafficcontrol signals to replacements for incandescent and fluorescent sourcelighting.

The inventive manufacturing process starts with a roll of flexible,plastic substrate. (1) A conductive electrode pattern is formed on thesubstrate through a variety of well-known printing techniques, such asinkjet printing. This electrode pattern is used to bring power to thechips. (2) Next, a conductive adhesive is printed at locations where theLED chips will be patterned. (3) Then, using an electrostatic drum andcharge patterning mechanism similar to a laser printer engine, LED chipsare patterned onto the electrostatic drum. The chip pattern is thentransferred to the adhesive areas that have been formed on thesubstrate. (4) A top substrate coated with a conductor is then broughtin to complete the solid-state, ultra thin, flexible light sheetsandwich. (5) Finally, the completed light sheet is rolled up on atake-up reel. This light sheet material can then be cut, stamped,thermoformed, bent and packaged into a wide range of new and usefulsolid-state lighting products.

In accordance with the invention, a method is provided for forming asheet of light active material. A first substrate (bottom substrate,shown in FIG. 1) is provided having a transparent first conductivelayer. The first substrate may be, for example, glass, flexible glass(available from Corning), PET, PAN, or other suitable polymer, Barrix(available from Vitrex) or other transparent or semi-transparentsubstrate material. The transparent first conductive layer may be, forexample, sputter coated indium-tin-oxide (ITO), a conductive polymer, athin metal film, or the like.

A pattern of light active semiconductor elements are formed. The lightactive semiconductor elements may be, for example, LED chips having ann-side and a p-side and/or light-to-energy semiconductor layeredparticles wherein the n- and p-side correspond to charge donor andcharge acceptor layers. Each light active semiconductor element haseither of the n-side or the p-side in electrical communication with thetransparent conductive layer. The electrical communication may be direct(i.e., surface to surface contact) or indirect (i.e., through aconductive or semi-conductive medium). A second substrate having asecond conductive layer is provided. The second substrate may be, forexample, a metal foil, a metal coated polymer sheet, a conductivepolymer coated metal foil or polymer sheet, or the like. The secondsubstrate is secured to the first substrate so that the other of saidn-side or said p-side of each said light active semiconductor element inelectrical communication with the second conductive layer. Again, theelectrical communication can be direct or indirect. Thus, in accordancewith the present invention, a solid-state sheet of light active materialis formed.

The transparent first conductive layer may comprise a transparentcoating preformed on the first substrate. For example, the substrate maybe a sheet or roll of a polymer film, such as PET or PAN, with a sputtercoated conductor comprised of ITO. Alternatively, as shown in FIG. 1,the transparent coating can be applied as a conductive ink or conductiveadhesive.

The pattern of light active semiconductor elements can be formed byelectrostatically attracting the light active semiconductor elements toa transfer member. Then, the attracted light active semiconductorelements are transferred from the transfer member to the firstsubstrate. The transfer member may include an opto-electric coatingeffective for holding a patterned electrostatic charge. The patternedelectrostatic charge is effective for electrostatically attracting thelight active semiconductor elements and forming the pattern of lightactive semiconductor elements. The optical patterning of theopto-electric coating can be done, for example, using a scanned laserbeam and an LED light source, similar to the process used by laser orLED printers. Thus, the transfer member may comprise an opto-electriccoated drum, and the patterning mechanism may be similar to thewell-know mechanism employed for patterning toner in a laser or LEDprinter.

An adhesive pattern can be formed on the first substrate for adheringthe pattern of light active semiconductor elements to the firstsubstrate. Alternatively, or additionally, an adhesive pattern can alsobe formed on the first substrate for adhering the second substrate tothe first substrate.

A pattern of light active semiconductor elements can be formed byforming a first pattern of first light active semiconductor elements andforming a second pattern of second light active semiconductor elements.The first light active semiconductor elements emit light having a firstcolor and the second light active semiconductor elements emit lighthaving a second color. Alternatively, the first light activesemiconductor elements emit light and the second light activesemiconductor elements convert light to electrical energy.

The first conductive layer may be formed as a grid of x-electrodes, andthe second conductive layer formed as a grid of y-electrodes, so thateach respective light active semiconductor element is addressable forforming a sheet of light active material capable of functioning as apixilated display component.

The pattern of light active semiconductor elements can be formed byforming a first pattern of first color light emitting semiconductorelements, forming a second pattern of second color light emittingsemiconductor elements and forming a third pattern of third color lightemitting semiconductor element. The first conductive layer may be formedas a grid of x-electrodes, and the second conductive layer formed as agrid of y-electrodes, so that each respective light active semiconductoris addressable for forming a sheet of light active material capable offunctioning as a full-color pixilated display component.

FIG. 2 illustrates another inventive method for manufacturing a lightactive sheet. In each example of the mechanism employed for forming theinventive light active sheet, the components and processes can be mixedin a number of iterations. The examples herein depict a selection ofsuch iterations, but represent just a few of the possible process andmaterial combinations contemplated by the inventive methods and devicestructures. As shown in FIG. 2, a first substrate is provided. A firstconductive surface is formed on the first substrate. A pattern of LEDchips is formed on the conductive surface. In the example shown, theconductive surface is provided as a conductive adhesive. However, theconductive surface may be, for example an ITO coating pre-formed on thebottom substrate. Each LED chip has an anode and a cathode side. Asecond substrate is provided. A second conductive surface is formed onthe second substrate. The first substrate is fixed to the secondsubstrate so that either of the anode and the cathode side of the LEDchip is in electrical communication with the first conductive surface,and the other of the anode and the cathode side of the LED chips is inelectrical communication with the second conductive surface. As shown,the LED chips may be encased within a conductive adhesive applied to thetop and bottom substrate, with an insulator adhesive applied between thechips. Alternatively, only an insulator adhesive may be applied betweenthe chips for fixing the top and bottom substrate together. The chipsare then held in electrical contact with the top and bottom substrateconductive surfaces through the clamping force applied by the insulatoradhesive. As other alternatives, only one or both of the substrates mayhave a conductive or non-conductive adhesive applied to it (throughinkjet, silkscreen, doctor blade, slot-die coating, electrostaticcoating, etc.), and the chips adhered directly or clamped between thesubstrates.

The first conductive surface may be formed as a conductive patterncomprised of at least one of a conductive coating, a conductive ink anda conductive adhesive. At least one of the first and the secondconductive surface is a transparent conductor. At least one of the firstand the second conductive surface is preformed on the respective firstand second substrate. The first conductive surface can be formed using aprinting method. The printing method may comprise at least one of aninkjet printing method, a laser printing method, a silk-screen printingmethod, a gravure printing method and a donor transfer sheet printingmethod.

An adhesive layer may be formed between the top substrate and the bottomsubstrate. The adhesive layer may comprise at least one of a conductiveadhesive, a semi-conductive adhesive, an insulative adhesive, aconductive polymer, a semi-conductive polymer, and an insulativepolymer. A function-enhancing layer can be formed between the topsubstrate layer and the bottom substrate layer. The function-enhancinglayer includes at least one of a re-emitter, a light-scatterer, anadhesive, and a conductor.

The pattern of LED chips can be formed by electrostatically attractingthe LED chips to a transfer member, and then transferring the attractedLED chips from the transfer member to the first conductive surface. Thetransfer member may include an opto-electric coating effective forholding a patterned electrostatic charge, the patterned electrostaticcharge being effective for electrostatically attracting and forming thepattern of LED chips. The the opto-electric coating can be patternedusing at least one of a scanned laser beam and an LED light source. Thetransfer member may be a drum, a flat planar member, or other shape. Themethod of transferring the chips may also include a pick-and-placerobotic method, or simple sprinkling of the semiconductor elements(i.e., the chips) onto an adhesive surface applied to the substrate.

FIG. 3 illustrates another inventive method for manufacturing a lightactive sheet having two or more different types of light activesemiconductor elements. A pattern of light active semiconductor elementscan be formed by forming a first pattern of first light activesemiconductor elements and forming a second pattern of second lightactive semiconductor elements. The first light active semiconductorelements emit light having a first color and the second light activesemiconductor elements emit light having a second color. Alternatively,the first light active semiconductor elements emit light and the secondlight active semiconductor elements convert light to electrical energy.

The first conductive layer may be formed as a grid of x-electrodes, andthe second conductive layer formed as a grid of y-electrodes, so thateach respective light active semiconductor element is addressable forforming a sheet of light active material capable of functioning as apixilated display component.

The pattern of light active semiconductor elements can be formed byforming a first pattern of first color light emitting semiconductorelements, forming a second pattern of second color light emittingsemiconductor elements and forming a third pattern of third color lightemitting semiconductor element. The first conductive layer may be formedas a grid of x-electrodes, and the second conductive layer formed as agrid of y-electrodes, so that each respective light active semiconductoris addressable for forming a sheet of light active material capable offunctioning as a full-color pixilated display component.

The inventive methods shown by way of example in FIGS. 1-3 can beemployed for creating a roll-to-roll or sheet manufacturing process formaking light emitting sheet material or light-to-energy sheet material.In accordance with another aspect of the invention, a method is providedfor forming a light-to-energy device. A first substrate is provided. Afirst conductive surface is formed on the first substrate. A pattern ofsemiconductor elements is formed on the conductive pattern. Eachsemiconductor element comprises a charge donor side and a chargeacceptor side. For example, the semiconductor elements may comprise acrystalline silicone-based solar panel-type semiconductor layeredstructure. Alternatively, other semiconductor layered structures can beused for the semiconductor elements, including but not limited to,various thin film amorphous silicon semiconductor systems know in theart that have been particle-ized.

In accordance with the inventive method, a second conductive surface isformed on a second substrate. The first substrate is fixed to the secondsubstrate so that either of the charge donor and the charge acceptorside of the semiconductor elements is in electrical communication withthe first conductive surface and the other of the charge donor and thecharge acceptor side of the semiconductor elements is in electricalcommunication with the second conductive surface.

The first conductive surface is formed as a conductive pattern comprisedof at least one of a conductive coating, a conductive ink and aconductive adhesive. At least one of the first and the second conductivesurface is a transparent conductor. At least one of the first and thesecond conductive surface is preformed on the respective first andsecond substrate. The first conductive surface may be formed using aprinting method. The printing method may comprise at least one of aninkjet printing method, a laser printing method, a silk-screen printingmethod, a gravure printing method and a donor transfer sheet printingmethod.

An adhesive layer can be formed between the top substrate and the bottomsubstrate. The adhesive layer may comprise at least one of a conductiveadhesive, a semi-conductive adhesive, an insulative adhesive, aconductive polymer, a semi-conductive polymer, and an insulativepolymer. A function-enhancing layer can be formed between the topsubstrate layer and the bottom substrate layer, wherein thefunction-enhancing layer includes at least one of a re-emitter, alight-scatterer, an adhesive, and a conductor.

The pattern of LED chips can be formed by electrostatically attractingthe LED chips to a transfer member, and then transferring the attractedLED chips from the transfer member to the first conductive surface. Thetransfer member may include an opto-electric coating effective forholding a patterned electrostatic charge, the patterned electrostaticcharge being effective for electrostatically attracting and forming thepattern of LED chips. The opto-electric coating can be patterned usingat least one of a scanned laser beam and an LED light source. Thetransfer member may be shaped as a drum, a flat planar member, or othershape.

FIG. 4 is a cross-sectional view of an inventive light active sheethaving a conductive adhesive for fixing the substrates and/or the lightactive semiconductor elements in place. In accordance with this aspectof the invention, device structures are provide for sheets of lightactive material. The examples shown herein are illustrative of variousiterations of the device structure, and constituent parts in eachexample can be mixed in additional iterations not specifically describedherein.

A first substrate has a transparent first conductive layer. A pattern oflight active semiconductor elements fixed to the first substrate. Thelight active semiconductor elements have an n-side and a p-side. Eachlight active semiconductor element has either of the n-side or thep-side in electrical communication with the transparent conductivelayer. A second substrate has a second conductive layer. An adhesivesecures the second substrate to the first substrate so that the other ofsaid n-side or said p-side of each said light active semiconductorelement is in electrical communication with the second conductive layer.Thus, a solid-state light active device is formed.

The transparent first conductive layer may comprise a transparentcoating preformed on the first substrate. The transparent coating can bea conductive ink or conductive adhesive. An adhesive pattern may beformed on the first substrate for adhering the pattern of light activesemiconductor elements to the first substrate. Alternatively, oradditionally, an adhesive pattern may be formed on the first substratefor adhering the second substrate to the first substrate.

FIG. 5 is a cross-sectional view of an inventive light active sheethaving two different types of light active semiconductor elementsoriented to be driven with opposite polarity electrical energy. Thepattern of light active semiconductor elements may comprise a firstpattern of first light active semiconductor elements and a secondpattern of second light active semiconductor elements. The first lightactive semiconductor elements may emit light having a first color andthe second light active semiconductor elements emit light having asecond color. Alternatively, the first light active semiconductorelements may emit light and the second light active semiconductorelements convert light to electrical energy.

FIG. 6 is a cross-sectional view of an inventive light active sheethaving additives included between the substrates to improve the desiredlight active sheet properties. The inventive light-emitting devicecomprises a first substrate. A first conductive surface is formed on thefirst substrate. A pattern of LED chips is formed on the conductivepattern. Each LED chip has an anode and a cathode side. A secondsubstrate has a second conductive surface formed on it. An adhesivefixes the first substrate to the second substrate so that either of theanode and the cathode side of the LED chip is in electricalcommunication with the first conductive surface, and the other of theanode and the cathode side of the LED chips is in electricalcommunication with the second conductive surface.

The first conductive surface can be formed as a conductive patterncomprised of at least one of a conductive coating, a conductive ink anda conductive adhesive. At least one of the first and the secondconductive surface is a transparent conductor. At least one of the firstand the second conductive surface can be preformed on the respectivefirst and second substrate. The first conductive surface can be formedusing a printing method. The printing method may comprise at least oneof an inkjet printing method, a laser printing method, a silk-screenprinting method, a gravure printing method and a donor transfer sheetprinting method.

The adhesive layer can comprise at least one of the top substrate andthe bottom substrate. The adhesive layer can comprise at least one of aconductive adhesive, a semi-conductive adhesive, an insulative adhesive,a conductive polymer, a semi-conductive polymer, and an insulativepolymer. A function-enhancing layer can be formed between the topsubstrate layer and the bottom substrate layer. The function-enhancinglayer may include at least one of a re-emitter, a light-scatterer, anadhesive, and a conductor.

FIG. 7 is a cross-sectional view of an inventive light active sheethaving the light active semiconductor elements disposed within asolid-state electrolyte. In accordance with an embodiment of theinventive light active sheet, a top PET substrate has a coating of ITO,acting as the top electrode. A bottom PET substrate can be ITO PET,metal foil, metalized mylar, etc., depending on the intended applicationof the light sheet (e.g., transparent HUD element, light source, solarpanel, etc.). The matrix (carrier) material may be a transparentphotopolymerizable solid polymer electrolyte (SPE) based on cross-linkedpolysiloxane-g-oglio9ethylene oxide (see, for example, Solid polymerelectrolytes based on cross-linked polysiloxane-g-oligo(ethylene oxide):ionic conductivity and electrochemical properties, Journal of PowerSources 119-121 (2003) 448-453, which is incorporated by referenceherein). The emissive particulate may be commercially available LEDchips, such as an AlGaAs/AlGaAs Red LED Chip—TK 112UR, available fromTyntek, Taiwan). Alternatively the particulate may be comprised oflight-to-energy particles, having charge donor and charge acceptorsemiconductor layers, such as found in typical silicon-based solarpanels. In the case of an energy-to-light device (i.e., a light sheet),it may be preferable for the matrix material to be less electricallyconductive than the semiconductor elements so that the preferred path ofelectrical conductivity is through the light emitting elements. In thecase of a light-to-energy device (i.e., a solar panel), it may bepreferable for the matrix material to be more electrically conductivethan the semiconductor element so that charges separated at thedonor/acceptor interface effectively migrate to the top and bottomsubstrate electrodes.

FIG. 8 is a cross-section view of an inventive light active sheet havingthe light active semiconductor elements disposed within a solid-statecharge transport carrier. As an example of a candidate solid-statecharge transport carrier, an intrinsically conductive polymer,Poly(thieno[3,4-b]thiophene), has been shown to exhibit the necessaryelectronic, optical and mechanical properties. (see, for example,Poly(thieno[3,4-b]thiophene): A p- and n-Dopable PolythiopheneExhibiting High Optical Transparency in the Semiconducting State,Gregory A. Sotzing and Kyunghoon Lee, 7281 Macromolecules 2002, 35,7281-7286, which is incorporated by reference herein)

FIG. 9 is a cross-section view of an inventive light active sheet havingan insulator material disposed between the top and bottom substrates.The insulator may be an adhesive, such as an epoxy, heat-meltablepolymer, etc. As shown, the semiconductor elements (e.g., LED chips) arefixed to the top and bottom substrates through a solid-state conductiveadhesive, charge transport carrier or solid-state electrolyte.Alternatively, the semiconductor elements may be in direct contact withthe top and bottom conductors disposed on the top and bottom substrates,and the adhesive provided between the LED chips to secure the top andsubstrates together and clamp the chips in electrical contact with thetop and bottom conductors.

FIG. 10 is a cross-sectional view of the inventive light active sheethaving an RGB semiconductor element pattern for forming a full-colorlight emissive display. The first conductive layer may be formed as agrid of x-electrodes, and the second conductive layer formed as a gridof y-electrodes. Each respective light active semiconductor element isdisposed at the respective intersections of the x and y grid and arethus addressable for forming a sheet of light active material capable offunctioning as a pixilated display component.

The pattern of light active semiconductor elements may comprise a firstpattern of first color light emitting semiconductor elements, a secondpattern of second color light emitting semiconductor elements and athird pattern of third color light emitting semiconductor element. Thefirst conductive layer may be formed as a grid of x-electrodes, and thesecond conductive layer being formed as a grid of y-electrodes. Therespective first, second and third color light emitting elements may bedisposed at the intersections of the x and y grid so that eachrespective light active semiconductor is addressable. Thus, a sheet oflight active material is formed capable of functioning as a full-colorpixilated display component.

FIG. 11 is a cross-sectional view of the inventive light active sheethaving a transparent substrate with a convex lens system. The substratemay be formed having a lens element disposed adjacent to eachpoint-source light emitter (LED chip), or an additional lens layer befixed to the substrate. The lens system may be concave for concentratingthe light output from each emitter (as shown in FIG. 11) or convex forcreating a more diffuse emission from the inventive light sheet (asshown in FIG. 12).

The devices shown, for example, in FIGS. 4-12, illustrate variousconfigurations of a light emitting sheet material. The LED chips shownare typical chips having top and bottom metal electrodes. However, inaccordance with the present invention, the proper selection of materials(conductive adhesives, charge transport materials, electrolytes,conductors, etc.) may enable LED chips to be employed that do notrequire either or both the top and bottom metal electrodes. In thiscase, since the metal electrode in a typical device blocks the lightoutput, the avoidance of the metal electrodes will effective increasethe device efficiency.

These devices may also be configured as a light to energy device. Inthis case, a first conductive surface is formed on the first substrate.A pattern of semiconductor elements is formed on the conductive pattern.Each semiconductor element includes a charge donor layer side and acharge acceptor side. A second substrate is provided having a secondconductive surface formed on it. An adhesive fixes the first substrateto the second substrate so that either of the charge donor and thecharge acceptor side of the semiconductor elements is in electricalcommunication with the first conductive surface, and the other of thecharge donor and the charge acceptor side of the semiconductor elementsis in electrical communication with the second conductive surface.

The first conductive surface may be formed as a conductive patterncomprised of at least one of a conductive coating, a conductive ink anda conductive adhesive. At least one of the first and the secondconductive surface is a transparent conductor. At least one of the firstand the second conductive surface may be preformed on the respectivefirst and second substrate. The adhesive may comprise at least one ofthe top substrate and the bottom substrate. The adhesive layer maycomprise at least one of a conductive adhesive, a semi-conductiveadhesive, an insulative adhesive, a conductive polymer, asemi-conductive polymer, and an insulative polymer.

FIG. 13 is an exploded view of the inventive light active sheet having amelt adhesive mesh. The melt adhesive sheet may be incorporated duringthe manufacture of the light active sheet at any suitable point. Forexample, it may be preformed on the bottom substrate before the LEDchips are transferred, and then after the chips are transferred to thespaces between the mesh, the top substrate applied. FIG. 14 is aschematic view of a method of manufacturing a light active sheetutilizing the melt adhesive mesh. In this case, heated pressure rollersmelt the melt adhesive mesh and compress the top and bottom substratestogether to effectively claim the LED chips into electrical contact withthe substrate conductors. Conductive adhesives, electrolytes, chargetransport materials, etc., as described herein may or may not benecessary, depending on the desire functional properties of thefabricated light active sheet.

FIG. 15 is an exploded view of the inventive light active sheetcomprising a substrate having position-facilitating chip dimples. FIG.16 is a cross-sectional view of the inventive light active sheet showingthe position-facilitating chip dimples. In this case, theposition-facilitating chip dimples may be provided to help locate andmaintain the positioning of the semiconductor elements.

FIG. 17 is an exploded view of the light active sheet having adhesivedroplets for fixing the semiconductor elements (chips) to the substrateand/or for adhering the top substrate to the bottom substrate. Theadhesive droplets can be preformed on the substrate(s) and may be heatmelt adhesive, epoxy, pressure sensitive adhesive, or the like.Alternatively, the adhesive droplets may be formed during theroll-to-roll or sheet fabrication process using, for example, inkjetprint heads, silkscreen printing, or the like. The adhesive droplets areprovided to hold the chips in place, and/or to secure the top substrateand the bottom substrate together.

FIG. 18 is an exploded view of the light active sheet having anelectrical resistance-reducing conductive grid pattern. The conductivegrid pattern can be provided to reduce sheet resistance and improve theelectrical characteristics of the fabricated light active sheetmaterial.

FIG. 19 is a schematic view of an inventive method of manufacturing alight active sheet wherein a hole-and-sprocket system is employed toensure registration of the constituent parts of the inventive lightsheet during the manufacturing process. The holes in the substrates (ora transfer sheet carrying the substrates) line up with the sprocketsthat may either be driven to move the substrates, and/or that may bedriven by the movement of the substrates. In either case, rotationalposition detection of the sprockets is used to control the variousactive elements of the manufacturing system to ensure accurateregistration between the constituent parts of the inventive light activesheet material.

FIG. 20 is an isolated view of an inventive semiconductor element (e.g.,LED chip) having a magnetically-attractive element to facilitate chiporientation and transfer. The chips may include a magnetically activeelectrode component, or an additional magnetically active component. Themagnetically active component enables the chips to be positioned andorient in response to an applied magnetic field. FIG. 21 illustrates theuse of a magnetic drum and electrostatic charge source for orienting andtransferring a pattern of semiconductor elements onto a substrate. FIG.22 illustrates the use of an electrostatic drum and magnetic attractionsource for orienting and transferring a pattern of semiconductorelements onto a substrate.

The inventive light sheet can be configured into a wide range ofapplications. FIG. 23 illustrates an inventive light active sheetthermoformed into a three-dimensional article. FIG. 24(a) illustrates aninventive light active sheet fabricated into a lampshade form-factorhaving a voltage conditioner for conditioning available electricalcurrent. FIG. 24(b) illustrates an inventive light active sheetfabricated into a light-bulb form-factor having a voltage conditionerfor conditioning available electrical current. FIG. 25 is across-sectional view of an inventive light sheet employed in the lightbulb and lampshade form factor show in FIGS. 24(a) and (b). FIG. 26(a)illustrates an inventive light sheet configured as a heads-up-display(HUD) installed as an element of a vehicle windshield. FIG. 26(b) is ablock diagram showing a driving circuit for an inventive HUD with acollision avoidance system. FIG. 27 is an exploded view of an inventivelight sheet utilized as a thin, bright, flexible, energy efficientbacklight component for an LCD display system.

FIG. 28 illustrates an embodiment of the inventive photo-radiationsource showing a semiconductor particulate randomly dispersed within aconductive carrier matrix. A light active device includes asemiconductor particulate dispersed within a carrier matrix material.

The carrier matrix material may be conductive, insulative orsemiconductor and allows charges to move through it to the semiconductorparticulate. The charges of opposite polarity moving into thesemiconductor material combine to form charge carrier matrix pairs. Thecharge carrier matrix pairs decay with the emission of photons, so thatlight radiation is emitted from the semiconductor material.Alternatively, the semiconductor material and other components of theinventive photo-radiation source may be selected so that light receivedin the semiconductor particulate generates a flow of electrons. In thiscase, the photo-radiation source acts as a light sensor.

A first contact layer or first electrode is provided so that onapplication of an electric field charge carrier matrix having a polarityare injected into the semiconductor particulate through the conductivecarrier matrix material. A second contact layer or second electrode isprovided so that on application of the electric field to the secondcontact layer charge carrier matrix having an opposite polarity areinjected into the semiconductor particulate through the conductivecarrier matrix material. To form a display device, the first contactlayer and the second contact layer can be arranged to form an array ofpixel electrodes. Each pixel includes a portion of the semiconductorparticulate dispersed within the conductive carrier matrix material.Each pixel is selectively addressable by applying a driving voltage tothe appropriate first contact electrode and the second contactelectrode.

The semiconductor particulate comprises at least one of an organic andan inorganic semiconductor. The semiconductor particulate can be, forexample, a doped inorganic particle, such as the emissive component of aconventional LED. The semiconductor particulate can be, for anotherexample, an organic light emitting diode particle. The semiconductorparticulate may also comprise a combination of organic and inorganicmaterials to impart characteristics such as voltage control emission,aligning field attractiveness, emission color, emission efficiency, andthe like.

The electrodes can be made from any suitable conductive materialincluding electrode materials that may be metals, degeneratesemiconductors, and conducting polymers. Examples of such materialsinclude a wide variety of conducting materials including, but notlimited to, indium-tin-oxide (“ITO”), metals such as gold, aluminum,calcium, silver, copper, indium and magnesium, alloys such asmagnesium-silver, conducting fibers such as carbon fibers, andhighly-conducting organic polymers such as highly-conducting dopedpolyaniline, highly-conducting doped polypyrole, or polyaniline salt(such as PAN-CSA) or other pyridyl nitrogen-containing polymer, such aspolypyridylvinylene. Other examples may include materials that wouldallow the devices to be constructed as hybrid devices through the use ofsemiconductor materials, such as n-doped silicon, n-doped polyacetyleneor n-doped polyparaphenylene.

As shown in FIG. 29, an embodiment of the inventive photo-radiationsource may have the semiconductor particulate aligned betweenelectrodes. The emissive particulate acts as point light sources withinthe carrier matrix material when holes and electrons are injected andrecombine forming excitons. The excitons decay with the emission ofradiation, such as light energy. In accordance with the presentinvention, the emissive particulate can be automatically aligned so thata significant majority of the point light sources are properly orientedand disposed between the electrodes (or array of electrodes in adisplay). This maximizes the light output from the device, greatlyreduces cross-talk between pixels, and creates a protected emissivestructure within the water, oxygen and contamination boundary providedby the hardened carrier matrix material.

In this case, the mixture disposed within the gap between the top andbottom electrodes includes a field reactive OLED particulate that israndomly dispersed within a fluid carrier matrix. An aligning field isapplied between the top electrode and the bottom electrode. The fieldreactive OLED particulate moves within the carrier matrix material underthe influence of the aligning field. Depending on the particulatecomposition, carrier matrix material and aligning field, the OLEDparticulates form chains between the electrodes (similar to theparticulate in an electrical or magnetic Theological fluid in anelectric or magnetic field), or otherwise becomes oriented in thealigning field. The aligning field is applied to form a desiredorientation of the field reactive OLED particulate within the fluidcarrier matrix. The fluid carrier matrix comprises a hardenablematerial. It can be organic or inorganic. While the desired orientationof the field reactive OLED particulate is maintained by the aligningfield, the carrier matrix is hardened to form a hardened supportstructure within which is locked in position the aligned OLEDparticulate.

FIG. 30 illustrates an embodiment of the inventive photo-radiationsource showing semiconductor particulate and other performance enhancingparticulate randomly dispersed within the conductive carrier matrixmaterial. The semiconductor particulate may comprise an organic lightactive particulate that includes at least one conjugated polymer. Theconjugated polymers having a sufficiently low concentration of extrinsiccharge carrier matrix. An electric field applied between the first andsecond contact layers causes holes and electrons to be injected into thesemiconductor particulate through the conductive carrier matrixmaterial. For example, the second contact layer becomes positiverelative to the first contact layer and charge carrier matrix ofopposite polarity is injected into the semiconductor particulate. Theopposite polarity charge carrier matrix combine to form in theconjugated polymer charge carrier matrix pairs or excitons, which emitradiation in the form of light energy.

Depending on the desired mechanical, chemical, electrical and opticalcharacteristics of the photo-radiation source, the conductive carriermatrix material can be a binder material with one or more characteristiccontrolling additives. For example, the binder material may be across-linkable monomer, or an epoxy, or other material into which thesemiconductor particulate can be dispersed. The characteristiccontrolling additives may be in a particulate and/or a fluid statewithin the binder. The characteristic controlling additives may include,for example, a desiccant, a scavenger, a conductive phase, asemiconductor phase, an insulative phase, a mechanical strengthenhancing phase, an adhesive enhancing phase, a hole injecting material,an electron injecting material, a low work metal, a blocking material,and an emission enhancing material. A particulate, such as an ITOparticulate, or a conductive metal, semiconductor, doped inorganic,doped organic, conjugated polymer, or the like can be added to controlthe conductivity and other electrical, mechanical and opticalcharacteristics. Color absorbing dyes can be included to control theoutput color from the device. Florescent and phosphorescent componentscan be incorporated. Reflective material or diffusive material can beincluded to enhance the absorption of received light (in the case, forexample, of a display or photodetector) or enhance the emitted lightqualities. In the case of a solar collector, the random dispersalorientation of the particulate may be preferred because it will enable asolar cell to have light receiving particulate that are randomlyoriented and the cell can receive light from the sun efficiently as itpasses over head. The orientation of the particulate may also becontrolled in a solar cell to provide a bias for preferred direction ofcapture light.

The characteristic controlling additives may also include materials thatact as heat sinks to improve the thermal stability of the OLEDmaterials. The low work metal additives can be used so that moreefficient materials can be used as the electrodes. The characteristiccontrolling additives can also be used to improve the mobility of thecarrier matrix in the organic materials and help improve the lightefficiency of the light-emitting device.

FIG. 31 illustrates an embodiment of the inventive photo-radiationsource showing different species of organic light active particulatedispersed within a carrier matrix material. The turn-on voltage for eachspecies can be different in polarity and/or magnitude. Emissions ofdifferent wavelengths or colors can be obtained from a single layer ofthe mixture of the organic light active particulate and carrier matrixmaterial. The color, duration and intensity of the emission is thusdependent on the controlled application of an electric field to theelectrodes. This structure has significant advantages over other fullcolor or multicolor light devices, and can also be configured as a widespectrum photodetector for applications such as cameras. The organiclight active particulate can include organic and inorganic particleconstituents including at least one of hole transport material, organicemitters, electron transport material, magnetic and electrostaticmaterial, insulators, semiconductors, conductors, and the like. As isdescribed herein, a multi-layered organic light active particulate canbe formed so that its optical, chemical, mechanical and electricalproperties are controlled by the various particle constituents.

FIG. 32 schematically illustrates the cross-section of an embodiment ofthe inventive photo-radiation source. The inventive photo-radiationsource for the selective polymerization of photo-radiation-curableorganic material includes a first electrode, and a second electrodedisposed adjacent to the first electrode and defining a gaptherebetween. The electrodes are disposed on top and bottom substrates,respectively. The substrates may be a flexible material, such aspolyester, PAN, or the like. One substrate may be transparent while theother is reflective.

A photo-radiation emission layer is disposed in the gap. Thephoto-radiation emission layer includes a charge-transport matrixmaterial and an emissive particulate dispersed within thecharge-transport matrix material. The emissive particulate receiveselectrical energy through the charge-transport matrix material. Theenergy is applied as a voltage to the first electrode, which may be ananode, and the second electrode, which may be a cathode. The emissiveparticulate generates photo-radiation in response to the appliedvoltage. This photo-radiation is effective for the selectivepolymerization of photo-radiation curable organic material.

In accordance with the present invention, a photo-radiation source isobtained that is effective for the photo-polymerization of apolymerizable organic material. The charge-transport matrix material maybe an ionic transport material, such as a fluid electrolyte or a solidelectrolyte, including a solid polymer electrolyte (SPE). The solidpolymer electrolyte may be a polymer electrolyte including at least oneof a polyethylene glycol, a polyethylene oxide, and a polyethylenesulfide. Alternatively or additionally, the charge-transport matrixmaterial may be an intrinsically conductive polymer. The intrinsicallyconductive polymer may include aromatic repeat units in a polymerbackbone. The intrinsically conductive polymer may be, for example, apolythiophene.

The charge-transport matrix material can be transparent tophoto-radiation in a photo-radiation spectrum effective for theselective polymerization of photo-radiation-curable organic material.The photo-radiation spectrum may comprise a range between and includingUV and blue light. The photo-radiation spectrum may include a rangebetween and including 365 and 405 nm. In a specific embodiment of theinvention, the photo-radiation spectrum emitted from the photo-radiationsource is in a range centered at around 420 nm.

The charge transport material transports electrical charges to theemissive particulate when a voltage is applied to the first electrodeand the second electrode. These charges are cause the emission ofphoto-radiation from the emissive particulate, this photo-radiationbeing effective for the selective polymerization ofphoto-radiation-curable organic material.

The emissive particulate is capable of emitting photo-radiation in aphoto-radiation spectrum effective for the selective polymerization ofphoto-radiation-curable organic material. The photo-radiation spectrummay comprise a range between and including UV and blue light. Thephoto-radiation spectrum may include a range between and including 365and 405 nm. In a specific embodiment of the invention, thephoto-radiation spectrum emitted from the emissive particulate is in arange centered at around 420 nm.

One of the first and the second electrode can be transparent to at leastof portion of photo-radiation emitted by the emissive particulate andthe other of the first and the second electrode can be reflective ofsaid at least a portion of the photo-radiation emitted by the emissiveparticulate.

The emissive particulate may comprise a semiconductor material, such asan organic and/or an inorganic multilayered semiconductor material. Thesemiconductor particulate can include an organic light activeparticulate including at least one conjugated polymer. The conjugatedpolymer has a sufficiently low concentration of extrinsic chargecarriers so that on applying an electric field between the first andsecond contact layers to the semiconductor particulate through theconductive carrier material the second contact layer becomes positiverelative to the first contact layer and charge carriers of said firstand second types are injected into the semiconductor particulate. Thecharge carriers combine to form in the conjugated polymer charge carrierpairs which decay radiatively so that radiation is emitted from theconjugated polymer. The organic light active particulate may compriseparticles including at least one of hole transport material, organicemitters, and electron transport material.

The organic light active particulate may comprise particles including apolymer blend, the polymer blend including an organic emitter blendedwith at least one of a hole transport material, an electron transportmaterial and a blocking material. The organic light active particulatemay comprise microcapsules including a polymer shell encapsulating aninternal phase comprised of a polymer blend including an organic emitterblended with at least one of a hole transport material, an electrontransport material and a blocking material.

The conductive carrier material may comprise a binder material with oneor more characteristic controlling additives. The characteristiccontrolling additives are at least one of a particulate and a fluidinclude a desiccant; a conductive phase, a semiconductor phase, aninsulative phase, a mechanical strength enhancing phase, an adhesiveenhancing phase, a hole injecting material, an electron injectingmaterial, a low work metal, a blocking material, and an emissionenhancing material.

FIG. 33 illustrates a step in an embodiment of the inventive method ofmaking a photo-radiation source. In this step, an emissiveparticulate/matrix mixture is applied onto a bottom substrate withbottom electrode. The particulate/matrix mixture can be applied ontosurface of the bottom electrode through a slot-die coating stage, or asshown herein, using a glass rod. At least one of the first electrode andthe second electrode may be transparent to photo-radiation in aphoto-radiation spectrum effective for the selective polymerization ofphoto-radiation-curable organic material. The first electrode and thesecond electrode can be planar and disposed on flexible substrates.

FIG. 34 illustrates a step in the inventive method of making aphoto-radiation source, showing the step of uniformly spreading theemissive particulate/matrix mixture onto the bottom electrode. In thiscase, the glass rod is pulled across the surface of the bottom electrodeto spread a uniformly thick layer of the emissive particulate/matrixmaterial. Spacers may be provided along the edges of the bottomelectrode to promote the uniformity of the spread mixture layer.

FIG. 35 illustrates a step in the inventive method of making aphoto-radiation source, showing the addition of a transparent topsubstrate with transparent top electrode over the emissiveparticulate/matrix mixture. At least one of the first electrode and thesecond electrode may be transparent to photo-radiation in aphoto-radiation spectrum effective for the selective polymerization ofphoto-radiation-curable organic material. The first electrode and thesecond electrode can be planar and disposed on flexible substrates. Thetop substrate and the top electrode may be transparent, with theelectrode material being indium tin oxide, a conjugated polymer, orother transparent conductor. The top substrate material can bepolyester, glass or other transparent substrate material.

FIG. 36 illustrates a step in the inventive method of making aphoto-radiation source, showing the step of photo-curing the matrix toform a solid-state emissive particulate/hardened matrix on the bottomsubstrate. Once the top substrate and top electrode are in place thematrix material can be hardened to form a solid-state device. The matrixmaterial can be a photo-polymerizable organic material, a two-partsystem such as a two-part epoxy, a thermally hardenable material, or thelike.

FIG. 37 illustrates a step in the inventive method of making aphoto-radiation source, showing the step of trimming the solid-statephoto-radiation source sheet. Once the solid-state device structure hasbeen obtained, the ends and edges can be trimmed as necessary ordesired. FIG. 3

1. A method of making a photo-radiation source comprising the steps of:providing a first planar conductor; disposing a formation of lightemitting chips on the first planar conductor, each chip having a cathodeand an anode, one of the cathode and anode of each chip being in contactwith the first planar conductor; disposing a second planar conductor ontop formation of light emitting chips so that the second planarconductor is in contact with the other of the cathode and anode of eachchip; binding the first planar conductor to the second planar conductorto permanently maintain the formation of light emitting chips withoutthe use of solder or wiring bonding for making an electrical andmechanical contact between the chips and either of the first planarconductor and the second planar conductor.
 2. A method of making aphoto-radiation source according to claim 38; wherein at least one ofthe first planar electrode and the second planar electrode istransparent.
 3. A method of making a photo-radiation source according toclaim 38; wherein the first planar electrode and the second planarelectrode are bound together by an adhesive disposed between the firstand second electrode.
 4. A method of making a photo-radiation sourceaccording to claim 38; wherein formation of light emitting chips arefixed to at least one of the first planar electrode and the secondplanar electrode by a binder material.
 5. A method of making aphoto-radiation source according to claim 41; wherein the bindermaterial comprises an intrinsically conductive polymer.
 6. A method ofmaking a photo-radiation source according to claim 41; wherein the firstplanar electrode and the second planar electrode are bound together bythe binder material that fixes the formation of light emitting chips.